JP2008100980A - ORGANIC SEMICONDUCTOR COMPOUND, ORGANIC SEMICONDUCTOR THIN FILM, ORGANIC SEMICONDUCTOR COATING LIQUID, ORGANIC THIN FILM TRANSISTOR, METHOD FOR PRODUCING BIS(BENZO[4,5]THIENO)[2,3-b:3'2'-e][1,4]DITHIIN AND BIS(BENZO[4,5]THIENO)[2,3-b:2'3'-e][1,4]DITHIIN - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new low-molecular organic semiconductor compound having high mobility and high solvent solubility, an organic semiconductor thin film and an organic semiconductor coating liquid containing the organic semiconductor compound, and an organic thin film transistor produced by using the new organic semiconductor compound as an active layer. <P>SOLUTION: The organic semiconductor compound is expressed by the general formula below, wherein A and B are each an aromatic ring with a conjugated electron system; X and Y are each DR<SB>2</SB>, ER or G; D is C, Si, Ge or Sn; E is N, P, As or Bi; G is O, S, Se or Te; and R is H, an alkyl group or an aryl group. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention particularly relates to an organic semiconductor compound, an organic semiconductor thin film, an organic semiconductor coating solution, and an organic thin film transistor having good solvent solubility and semiconductor characteristics. The present invention also provides bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin and bis (benzo [4,4] used as the organic semiconductor compound. 5) thieno) [2,3-b: 2'3'-e] [1,4] This invention relates to a novel process for producing dithiin.

  In recent years, organic semiconductor materials have attracted attention as semiconductor materials for TFTs (thin film transistors). Organic semiconductors can be easily formed into thin films by using simple techniques such as spin coating and vacuum deposition, and have a higher manufacturing process temperature than conventional TFTs using amorphous or polycrystalline silicon. There is an advantage that the temperature can be lowered. Lowering the process temperature enables formation on plastic substrates with low heat resistance, which is expected to reduce display weight and cost, and diversify applications by taking advantage of the flexibility of plastic substrates. The

  One of the important physical parameters in organic semiconductor materials is carrier mobility. Originally, organic semiconductor materials have a small intermolecular interaction and exert a strong individuality of the molecules themselves. Therefore, their mobility is smaller than that of inorganic semiconductor materials, which is a major obstacle to practical use. It was.

Organic semiconductor materials are roughly classified into two types, low molecular weight and high molecular weight. As low molecular weight systems, hydrocarbon systems such as acene compounds (see Patent Document 1), sulfur-containing compounds such as thiophene compounds, and nitrogen-containing compounds such as phthalocyanine compounds have been developed. As the polymer system, F8T2 (polyfluorene-thiophene copolymer) and P3HT (poly-3-hexylthiophene) have been developed.
International Publication No. 03/016599 Tetrahedron Lett., Vol. 45, 7943-7946 (2994)

  In general, a low molecular weight material has a higher mobility than a high molecular weight material, but has a drawback of poor productivity because of low solvent solubility. If the solvent solubility can be improved, a method such as an ink jet method can be adopted, and the cost can be reduced. As described above, a novel low molecular weight organic semiconductor material having improved both mobility and solvent solubility is desired.

A specific aspect of the present invention is to provide a novel low-molecular organic semiconductor compound having high mobility and solvent solubility, an organic semiconductor thin film containing the organic semiconductor compound, and an organic semiconductor coating solution.
A specific aspect of the present invention aims to provide an organic thin film transistor using a novel organic semiconductor compound as an active layer.
Specific embodiments according to the present invention include bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin and bis (benzoate) used as the organic semiconductor compound. [4,5] thieno) [2,3-b: 2′3′-e] [1,4] The present invention relates to a novel method for producing dithiin.

により表される。
（式中、Ａ、Ｂは電子共役系芳香環であり、Ｘ、Ｙは、それぞれＤＲ₂、ＥＲ、Ｇである。ＤはＣ、Ｓｉ、Ｇｅ、Ｓｎのいずれかであり、ＥはＮ、Ｐ、Ａｓ、Ｂｉのいずれかであり、ＧはＯ、Ｓ、Ｓｅ、Ｔｅのいずれかである。Ｒは、Ｈ、アルキル基、アリール基のいずれかである。） The organic semiconductor compound according to the present invention has the general formula

Is represented by
(In the formula, A and B are electron conjugated aromatic rings, X and Y are DR ₂ , ER and G, respectively. D is any one of C, Si, Ge and Sn, and E is N, (It is any one of P, As, and Bi, G is any one of O, S, Se, and Te. R is any one of H, an alkyl group, and an aryl group.)

The organic semiconductor compound according to the present invention is of a low molecular weight type and has a structure in which aromatic rings A and B are connected by a central connecting ring. Since the aromatic rings A and B are electron conjugated systems, they have a planar structure. On the other hand, since the connecting ring is not an electron conjugated system, it has a bent structure. By connecting the electron-conjugated aromatic rings A and B with a linking ring having a bent structure, a space into which solvent molecules enter is intentionally formed. Thereby, the solubility to a solvent can be improved.
In addition, since the aromatic rings A and B are electron conjugated systems, that is, have electrons that can move around, it can be said that the organic compound in which the aromatic rings A and B are connected by a connecting ring has semiconductor characteristics as a whole. Further, in the organic semiconductor compound according to the present embodiment, the aromatic rings A and B and the connecting ring are connected in such a manner that a side (referring to a bond between two atoms) is shared. As a result, even if the linking ring itself is not an electron conjugated system, it can be expected to interact with the aromatic rings A and B to amplify the effect of the conjugated system of both aromatic rings A and B.
Further, when Group 15 or Group 16 is employed as X and Y, it is expected that the linked ring changes to a conjugated system by one-electron oxidation or two-electron oxidation (electron emission) after film formation. In order to cause this change, it is also effective to give an external field (electric field, magnetic field, etc.) or energy (heat, etc.) after film formation as necessary. Thereby, while exhibiting high solubility in a solvent, an organic semiconductor compound exhibiting high carrier mobility can be provided by extending the π-conjugated system after film formation.

により表されるビス（ベンゾ［４，５］チエノ）［２，３−ｂ：３’２’−ｅ］［１，４］ジチインである。 Preferably, the structural formula

Bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin represented by:

により表されるビス（ベンゾ［４，５］チエノ）［２，３−ｂ：２’３’−ｅ］［１，４］ジチインである。 Or, preferably, the structural formula

Bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by:

  The organic semiconductor thin film according to the present invention contains the organic semiconductor compound. Thereby, the organic-semiconductor thin film which raised carrier mobility is realizable.

  The organic semiconductor coating liquid according to the present invention contains the organic semiconductor compound and a solvent capable of dissolving the organic semiconductor compound. Since the organic semiconductor compound according to the present invention has high solubility in a solvent, an organic semiconductor coating liquid can be prepared. By applying this organic semiconductor coating liquid, an organic semiconductor thin film can be produced at low cost.

  The solvent includes at least one of hydrocarbon, alcohol, ether, ester, halogen, ketone, nitrile, BTX, and aprotic polar solvent. Thereby, an organic semiconductor compound can be dissolved.

  The organic thin-film transistor which concerns on this invention is an organic thin-film transistor provided with an organic-semiconductor thin film as an active layer, Comprising: The said organic-semiconductor thin film contains the said organic-semiconductor compound. Thereby, an organic thin film transistor with improved carrier mobility and productivity can be realized.

で表される３，３’−ビス（ベンゾ［ｂ］チエニル）スルフィドのジブロモ体を生成し、当該ジブロモ体をジアニオン体化し、二塩化硫黄を加えることを特徴とする、構造式

で表されるビス（ベンゾ［４，５］チエノ）［２，３−ｂ：３’２’−ｅ］［１，４］ジチインの製造方法である。 Furthermore, the present invention provides a structural formula

A dibromo form of 3,3′-bis (benzo [b] thienyl) sulfide represented by the formula: wherein the dibromo form is converted into a dianion form, and sulfur dichloride is added.

And bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin represented by the formula:

  According to the present invention, the yield of bis (benzo [4,5] thieno) [2,3-b: 3'2'-e] [1,4] dithiin can be improved.

で表されるベンゾ［ｂ］チオフェンから、構造式

で表される２，３’−ビス（ベンゾ［ｂ］チエニル）スルフィドを経て、構造式

で表されるビス（ベンゾ［４，５］チエノ）［２，３−ｂ：２’３’−ｅ］［１，４］ジチインを製造する方法であって、
ベンゾ［ｂ］チオフェンから、構造式

で表される２−アセチルチオベンゾ［ｂ］チオフェンを経て２，３’−ビス（ベンゾ［ｂ］チエニル）スルフィドを生成することを特徴とする、ビス（ベンゾ［４，５］チエノ）［２，３−ｂ：２’３’−ｅ］［１，４］ジチインの製造方法である。 The present invention also has the structural formula

From the benzo [b] thiophene represented by the structural formula

And 2,3′-bis (benzo [b] thienyl) sulfide represented by the structural formula

A bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by the formula:
From benzo [b] thiophene, the structural formula

Bis (benzo [4,5] thieno) [2], characterized in that 2,3′-bis (benzo [b] thienyl) sulfide is produced via 2-acetylthiobenzo [b] thiophene represented by , 3-b: 2′3′-e] [1,4] dithiin.

  According to the present invention, since the yield of 2,3′-bis (benzo [b] thienyl) sulfide can be improved, the final product, bis (benzo [4,5] thieno) [2, 3-b: 2′3′-e] [1,4] dithiin yield can be improved.

で表される２，３’−ビス（ベンゾ［ｂ］チエニル）スルフィドをジブロモ体とした後、当該ジブロモ体をジリチオ化し、硫黄化環化反応させることを特徴とする、構造式

で表されるビス（ベンゾ［４，５］チエノ）［２，３−ｂ：２’３’−ｅ］［１，４］ジチインの製造方法である。 Furthermore, the present invention provides a structural formula

The structure represented by the structural formula is characterized in that the 2,3′-bis (benzo [b] thienyl) sulfide represented by the following formula is converted into a dibromo form, and then the dibromo form is dilithiated and subjected to a sulfurization cyclization reaction.

And bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by the formula:

  According to the present invention, bis (benzo [4,5] thieno) [2,3-b: 2'3'-e] [1,4] dithiin can be produced at low cost.

<Organic semiconductor compound>
Embodiments of the present invention will be described below with reference to the drawings.

により表される。
（式中、Ａ、Ｂは電子共役系芳香環であり、Ｘ、Ｙは、それぞれＤＲ₂、ＥＲ、Ｇである。ＤはＣ、Ｓｉ、Ｇｅ、Ｓｎのいずれかであり、ＥはＮ、Ｐ、Ａｓ、Ｂｉのいずれかであり、ＧはＯ、Ｓ、Ｓｅ、Ｔｅのいずれかである。Ｒは、Ｈ、アルキル基、アリール基のいずれかである。） The organic semiconductor compound according to this embodiment has a general formula

Is represented by
(In the formula, A and B are electron conjugated aromatic rings, X and Y are DR ₂ , ER and G, respectively. D is any one of C, Si, Ge and Sn, and E is N, (It is any one of P, As, and Bi, G is any one of O, S, Se, and Te. R is any one of H, an alkyl group, and an aryl group.)

で表される連結環で連結させた縮合環化合物である。本実施形態に係る有機半導体化合物は、連結環と電子共役系芳香環で辺（２つの原子間の結合をいう）を共有した縮合環化合物である。 The above organic compound has two electron conjugated aromatic rings A and B represented by the general formula

It is a condensed ring compound connected by the connection ring represented by these. The organic semiconductor compound according to the present embodiment is a condensed ring compound in which a linking ring and an electron-conjugated aromatic ring share a side (referring to a bond between two atoms).

The aromatic rings A and B only have to be π-electron conjugated systems, and may be composed of only hydrocarbons or may contain elements other than carbon. The aromatic rings A and B may have only one ring or two or more rings. The aromatic rings A and B may be the same or different. Examples of the aromatic rings A and B include those shown below.

X and Y of the linking ring are DR ₂ , ER and G, respectively. D is any one of group 14 C, Si, Ge, and Sn, E is any one of group 15, N, P, As, and Bi, and G is any of group 16, O, S, Se, and Te It is. R is any one of H (hydrogen), an alkyl group, and an aryl group. When X and Y are composed of the above ER or G, examples of the linking ring include those shown below.

X of the connecting ring, Y is, in the case of the DR ₂ include those shown below as the structure of the connecting ring. R is H (hydrogen), an alkyl group, or an aryl group.

The effect of the organic semiconductor compound will be described in the above embodiment. The organic semiconductor compound according to this embodiment is of a low molecular weight type. The organic semiconductor compound according to this embodiment has a planar structure because the aromatic rings A and B are π electron conjugated systems. In contrast, the linking ring is not a π-electron conjugated system but has a bent structure. By connecting the electron-conjugated aromatic rings A and B with a linking ring having a bent structure, a space into which solvent molecules enter is intentionally formed. Thereby, the solubility to the solvent of the organic compound which concerns on this embodiment can be improved.

  In addition, since the aromatic rings A and B are π-electron conjugated systems, that is, have electrons that can move around, it can be said that the organic compound in which the aromatic rings A and B are connected by a connecting ring has semiconductor characteristics as a whole. Further, in the organic semiconductor compound according to the present embodiment, the aromatic rings A and B and the connecting ring are connected in such a manner that a side (referring to a bond between two atoms) is shared. As a result, even if the linking ring itself is not a π-electron conjugated system, it can be expected to interact with the aromatic rings A and B to amplify the effect of the conjugated system of both aromatic rings A and B.

  Further, when Group 15 or Group 16 is employed as X and Y, it is expected that the linked ring changes to a conjugated system by one-electron oxidation or two-electron oxidation (electron emission) after film formation. In order to cause this change, it is also effective to give an external field (electric field, magnetic field, etc.) or energy (heat, etc.) after film formation as necessary. Thereby, while exhibiting high solubility in a solvent, an organic semiconductor compound exhibiting high carrier mobility can be provided by extending the π-conjugated system after film formation.

<Organic semiconductor thin film>
The organic semiconductor thin film according to the present embodiment mainly contains the organic semiconductor compound described above. The organic semiconductor thin film according to this embodiment can be formed by forming a thin film using the organic semiconductor compound and then patterning as necessary.

  The organic semiconductor thin film can be formed by, for example, chemical vapor deposition (CVD), vacuum vapor deposition, or coating method, and is preferably formed by a simple coating method. In the coating method, after applying a solution obtained by dissolving the above-described organic semiconductor compound in a solvent, post-treatment (for example, heating, infrared irradiation, application of ultrasonic waves, etc.) is applied to this coating film as necessary. By applying this, an organic semiconductor thin film can be formed. Here, examples of the coating method include spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen printing. , Flexographic printing method, offset printing method, ink jet method, microcontact printing method and the like, and one or more of them can be used in combination.

Among these, it is preferable to form an organic semiconductor thin film using an inkjet method. According to the inkjet method, an organic semiconductor thin film can be formed only in a desired region without forming a resist mask. Thereby, the usage-amount of material can be reduced and the reduction of manufacturing cost can be aimed at. Further, by using the ink jet method, it is not necessary to use chemicals such as a photoresist, a developer, a stripping solution, or a plasma treatment such as oxygen plasma or CF ₄ plasma. Therefore, there is no possibility that the characteristics of the organic semiconductor material are changed (for example, doped) or deteriorated.

<Organic semiconductor coating solution>
The organic semiconductor coating liquid according to the present embodiment includes the above-described organic semiconductor compound and a solvent that dissolves the organic semiconductor compound. Content of the organic-semiconductor compound in a coating liquid is adjusted with the coating method and the film thickness of the target organic-semiconductor thin film. When the ink jet method is used, the amount and type of the solvent are adjusted so that the viscosity and the contact angle are suitable for discharging from the droplet discharge device.

  As a solvent for dissolving the organic semiconductor compound material according to the present embodiment, hydrocarbon-based, alcohol-based, ether-based, ester-based, halogen-based, ketone-based, nitrile-based, BTX-based, aprotic polar solvent, or a mixture thereof A solvent can be used. Examples of the hydrocarbon type include hexane, heptane, octane, and cyclohexane. Examples of alcohols include methanol, ethanol, (iso) propanol, and butanol. Examples of ethers include diethyl ether, tetrahydrofuran, and dioxane. Examples of the ester type include ethyl acetate and butyl acetate. Examples of the halogen type include dichloromethane and chloroform. Examples of ketones include acetone and methyl ethyl ketone. Examples of the nitrile system include acetonitrile and methyl ethyl ketone. BTX system is hexane, toluene, xylene. Examples of the aprotic polar solvent include dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and hexamethylphosphorus amide (HMPA).

<Organic thin film transistor>
FIG. 1 is a cross-sectional view of an organic thin film transistor according to this embodiment.
An organic thin film transistor 10 shown in FIG. 1 includes a gate electrode 12 provided on a substrate 11, a gate insulating film 13 provided on the gate electrode 12, and a source electrode 14 and a drain electrode 15 provided on the gate insulating film 13. And an organic semiconductor thin film 17 provided via a modification film 16 on the gate insulating film 13 between the source electrode 14 and the drain electrode 15.

  The organic thin film transistor 10 is a thin film transistor having a configuration in which the gate electrode 12 is provided closer to the substrate 11 than the organic semiconductor thin film 17 serving as an active layer, that is, a bottom gate thin film transistor. However, the organic semiconductor thin film 17 may have another structure such as a thin film transistor having a configuration in which the organic semiconductor thin film 17 is provided on the substrate 11 side with respect to the gate electrode 12, that is, a thin film transistor having a top gate structure.

Hereinafter, each part which comprises the organic thin-film transistor 10 is demonstrated sequentially.
The substrate 11 supports each layer (each part) constituting the organic thin film transistor 10. Examples of the substrate 11 include a glass substrate, polyimide, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polymethyl methacrylate (PMMA), polycarbonate (PC), polyethersulfone (PES), and aromatic polyester (liquid crystal polymer). Or the like, a plastic substrate (resin substrate), a quartz substrate, a silicon substrate, a gallium arsenide substrate, or the like can be used. When the organic thin film transistor 10 is given flexibility, a resin substrate is selected as the substrate 11.

The gate electrode 12 may be a conductive material such as a metal material or a metal oxide material, or a conductive region formed by introducing impurities into the substrate 11. For example, Ag, Pd, Pt, Au, W, Ta, Mo, Al, Cr, Ti, Cu and Ni or alloys containing these, indium tin oxide (ITO), indium oxide (IO), indium zinc oxide (IZO) Antimontin oxide (ATO), tin oxide (SnO ₂ ), and the like, and one or more of these can be used in combination.

  The gate insulating film 13 insulates the gate electrode 12 from the source electrode 14 and the drain electrode 15 and may be made of either an inorganic material or an organic material (particularly an organic polymer material). An example of the inorganic material used for the gate insulating film 13 is silicon oxide. As an organic polymer material to be the gate insulating film 13, an acrylic resin such as polystyrene, polyimide, polyamideimide, polyvinylphenylene, polycarbonate (PC), polymethyl methacrylate (PMMA), or polytetrafluoroethylene (PTFE). Fluorine resin, phenolic resin such as polyvinylphenol or novolac resin, and olefinic resins such as polyethylene, polypropylene, polyisobutylene, polybutene, etc. are used, and one or more of these may be used in combination. it can. Note that the gate insulating film 13 is not limited to a single layer structure, and may have a multilayer structure.

The constituent material of the source electrode 14 and the drain electrode 15 is not particularly limited as long as it has conductivity. For example, Pd, Pt, Au, W, Ta, Mo, Al, Cr, Ti, Cu or these may be used. Conductive materials such as alloys, conductive oxides such as ITO, FTO, ATO, SnO ₂ , carbon-based materials such as carbon black, carbon nanotubes, fullerene, polyacetylene, polypyrrole, polythiophene such as PEDOT (poly-ethylenedioxythiophene) , Conductive polymer materials such as polyaniline, poly (p-phenylene), polyfluorene, polycarbazole, polysilane, or derivatives thereof can be used, and one or more of these can be used in combination. . The conductive polymer material is usually used in a state of being doped with a polymer such as iron oxide, iodine, inorganic acid, organic acid, polystyrene sulphonic acid and imparted with conductivity. Among these, materials mainly composed of Ni, Cu, Co, Au, Pd, or alloys containing these are suitably used as the constituent materials of the source electrode 14 and the drain electrode 15.

  The modification film 16 promotes adhesion of the organic semiconductor thin film 17 to the gate insulating film 13 and is provided as necessary. For example, hexamethylsilazane is used as the modification film 16.

  The organic semiconductor thin film 17 includes the organic semiconductor compound according to this embodiment. The thickness (average) of the organic semiconductor thin film 17 is preferably about 0.1 to 1000 nm, more preferably about 1 to 500 nm, and further preferably about 10 to 100 nm.

  In the organic thin film transistor 10, the amount of current flowing between the source electrode 14 and the drain electrode 15 is controlled by changing the voltage applied to the gate electrode 12. That is, in the OFF state in which no voltage is applied to the gate electrode 12, even if a voltage is applied between the source electrode 14 and the drain electrode 15, almost no carriers are present in the organic semiconductor thin film 17. Only flows. On the other hand, in the ON state in which a voltage is applied to the gate electrode 12, carriers are induced in the portion of the organic semiconductor thin film 17 facing the gate insulating film 13, and a channel is formed. When a voltage is applied between the source electrode 14 and the drain electrode 15 in this state, electrons flow through the channel.

  The driving current of the transistor is proportional to the carrier (electron) mobility. In the present embodiment, by using a film containing the above-described organic semiconductor compound as the organic semiconductor thin film 17, the carrier mobility can be increased and the driving current of the organic thin film transistor can be increased.

<Method for Manufacturing Thin Film Transistor>
FIG. 2 is a process cross-sectional view for explaining the manufacturing method of the thin film transistor 1.
As shown in FIG. 2A, a gate electrode 12 having a desired pattern is formed on a substrate 11. As a method for forming the gate electrode 12, an ink jet method for discharging a liquid material containing conductive particles or a lift-off method can be used. Alternatively, after forming the conductive film, a resist mask may be formed by a lithography technique, and the conductive film may be etched using the resist mask to form the gate electrode. When a silicon substrate is used as the substrate 11, the gate electrode 12 may be formed by introducing impurities into the silicon substrate.

  Subsequently, a gate insulating film 13 is formed on the gate electrode 12. For example, the gate insulating film 13 is applied (supplied) onto the gate insulating film 13 by using a coating method with a solution containing an insulating material or a precursor thereof, and then applied to the coating film as necessary. It can be formed by performing treatment (for example, heating, irradiation with infrared rays, application of ultrasonic waves, etc.). Alternatively, the gate insulating film 13 may be formed using an inkjet method. Alternatively, the gate insulating film 13 made of silicon oxide may be formed by thermally oxidizing the surface of the silicon substrate.

  Next, as shown in FIG. 2B, after forming a conductive film on the gate insulating film 13, the conductive film is patterned to form the source electrode 14 and the drain electrode 15.

  The conductive film is, for example, a chemical vapor deposition method (CVD) such as plasma CVD, thermal CVD, or laser CVD, a dry plating method such as vacuum deposition, sputtering, or ion plating, or a wet method such as electrolytic plating, immersion plating, or electroless plating. It can be formed by a plating method, a thermal spraying method, a sol-gel method, and a MOD method.

  The patterning is performed by forming a resist mask on the conductive film by lithography and then etching the conductive film using the resist mask. This etching can be performed by combining one or more of physical etching methods such as plasma etching, reactive etching, beam etching, and light assisted etching, and chemical etching methods such as wet etching. Among these, it is preferable to use wet etching. Thereafter, the resist mask is removed.

  Note that the source electrode 14 and the drain electrode 15 may be formed by a lift-off method. That is, a resist mask having openings corresponding to the shapes of the source electrode 14 and the drain electrode 15 is formed on the substrate 11, and a conductive film is deposited on the substrate 11 on which the resist mask is formed. After that, by peeling off the resist mask, the conductive film remains only in the opening of the resist mask, so that the source electrode 14 and the drain electrode 15 can be obtained.

  Next, as shown in FIG. 2C, a modification film 16 is formed on the surface of the gate insulating film 13 exposed from the source electrode 14 and the drain electrode 15. For example, hexamethyldisilazane is formed as the modification film 16 by the CVD method.

  Next, as shown in FIG. 2D, an organic semiconductor thin film 17 is formed on the modification film 16 using the organic semiconductor compound according to this embodiment.

  The organic semiconductor thin film 17 can be formed by, for example, chemical vapor deposition (CVD), vacuum vapor deposition, or coating method, and is preferably formed by a simple coating method. In the coating method, after applying a solution obtained by dissolving the above-described organic semiconductor compound in a solvent, post-treatment (for example, heating, infrared irradiation, application of ultrasonic waves, etc.) is applied to this coating film as necessary. By applying this, an organic semiconductor thin film can be formed.

Among the coating methods, it is preferable to form the organic semiconductor thin film using an inkjet method. According to the inkjet method, an organic semiconductor thin film can be formed only in a desired region without forming a resist mask. Thereby, the usage-amount of material can be reduced and the reduction of manufacturing cost can be aimed at. Further, by using the ink jet method, it is not necessary to use chemicals such as a photoresist, a developer, a stripping solution, or a plasma treatment such as oxygen plasma or CF ₄ plasma. Therefore, there is no possibility that the characteristics of the organic semiconductor material are changed (for example, doped) or deteriorated.

Thus, the organic thin film transistor 10 according to this embodiment is obtained.
According to the method for manufacturing the organic thin film transistor 10 according to the present embodiment, the organic semiconductor thin film 17 can be formed using a coating method such as an ink jet method by using an organic semiconductor compound having high solvent solubility. Cost reduction of the thin film transistor 10 can be achieved.

  The organic thin film transistor 10 is used for an active matrix substrate of various display devices, for example. Examples of the display device include an electrophoretic display device, a liquid crystal display device, an organic EL display device, and an inorganic EL display device.

  These display devices are used as display units of various electronic devices. Examples of such electronic devices include televisions, electronic paper, viewfinder type or monitor direct-view type video tape recorders, car navigation devices, pagers, electronic notebooks, calculators, electronic newspapers, word processors, personal computers, workstations, videophones. , A POS terminal, a device equipped with a touch panel, and the like.

  Although the detailed Example of this invention is described below, this invention is not limited to this.

<Organic semiconductor compound>
In this example, benzo [b] thiophene rings were used as the aromatic rings A and B, and 1,4-dithiine was used as the linking ring. That is, the organic semiconductor compound of this example is a condensed ring compound of two benzo [b] thiophene rings and 1,4-dithiine.

により表されるｓｙｎ型のビス（ベンゾ［４，５］チエノ）［２，３−ｂ：３’２’−ｅ］［１，４］ジチインと、構造式

により表されるａｎｔｉ型のビス（ベンゾ［４，５］チエノ）［２，３−ｂ：２’３’−ｅ］［１，４］ジチインの２種類の構造異性体が存在する。 As this condensation compound, structural formula

A syn-type bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiine represented by the formula:

There are two types of structural isomers of the anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiine represented by:

  In the following, an organic thin film transistor is manufactured using syn-type bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiine, and the characteristics of the thin film transistor are evaluated. Was done. Hereinafter, a method for manufacturing the thin film transistor of the embodiment will be described with reference to FIGS.

<Method for Fabricating Organic Thin Film Transistor>
As a substrate 11 shown in FIG. 2A, a single crystal silicon substrate (silico wafer) doped with impurities was used, and a conductive region into which impurities were introduced was used as the gate electrode 12.

  Next, as shown in FIG. 2B, a gate insulating film 13 made of a thermal oxide film having a thickness of 300 nm was formed on the surface of the substrate 11. Subsequently, a pattern of the source electrode 14 and the drain electrode 15 made of gold (Au) was formed by a vacuum film forming method and a lithography method. The distance (channel length) between the source electrode 14 and the drain electrode 15 was 50 μm.

  Next, as shown in FIG. 2C, a modification film 22 is formed on the surface of the gate insulating film 13 by chemical vapor deposition (CVD) using hexamethyldisilazane (HMDS) which is a silane compound. Formed.

  Next, as shown in FIG. 2D, bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin is used by vacuum deposition. Thus, an organic semiconductor thin film 17 was formed. The film thickness of the organic semiconductor thin film 17 was 100 nm.

  The characteristics of the bottom gate type organic thin film transistor (gate electrode: n-type Si, channel length: L = 50 μm, channel width W = 2 mm) obtained by the above method were measured in vacuum. The measurement conditions were both p-channel and n-channel.

<Experimental result>
FIG. 3 shows I _D (drain current) -V _G (gate voltage) characteristics when V _D (drain voltage) = − 5 (V) is fixed, and the vertical axis is plotted in two ways, linear and log. It is. In FIG. 3, the left vertical axis is a linear axis, and the right vertical axis is a logarithmic axis.

From the results shown in FIG. 3, bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin has p-type semiconductor characteristics with a negative threshold voltage. It can be seen that From the log plot, the ON / OFF ratio of this device was about 105. From the linear plot, mobility μ = 5.0 × 10 ⁻³ cm ² / Vs and threshold voltage Vth = −60.5 V were obtained. On the other hand, no semiconductor characteristics were obtained under n-channel measurement conditions. The bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin of this example was confirmed to be soluble in the above-described solvent. In addition, it was confirmed that it exhibits higher solubility than conventional low-molecular organic semiconductor compounds.

  In Example 2, an organic thin film transistor was manufactured using anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin, and the thin film transistor Characterization was performed. A method for manufacturing the thin film transistor of Example 2 will be described below with reference to the drawings.

<Preparation of organic semiconductor single crystal>
In Example 2, first, a single crystal of the organic semiconductor thin film 17 is produced. For example, a single crystal made of anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin is produced by a technique called physical vapor transport. To do.

  FIG. 4 is a diagram for explaining the physical vapor transport method. In this method, first, as shown in FIG. 4, an inert gas such as argon is allowed to flow through a tubular electric furnace 9 to which a temperature gradient is applied, so that the upstream side of the tubular electric furnace 9 is heated to a higher temperature. Next, powdery organic semiconductor raw material 7, for example, anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin is added to the high temperature portion. The temperature is set so that anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin gradually sublimes in the high temperature part. And crystallize in the low temperature part downstream. Furthermore, the obtained crystal 8 is placed on the upstream portion again, and crystallization is repeated several times (for example, three times), whereby a high-purity organic semiconductor crystal can be obtained. In this way, a normal anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin single crystal having a flat surface is obtained. It was.

<Production of substrate>
As shown in FIG. 5A, a single crystal silicon substrate (silicon wafer) doped with impurities was used, and a conductive region into which impurities were introduced was used as the gate electrode 12. In FIG. 5, illustration of the substrate 11 is omitted. Subsequently, the surface of the conductive silicon wafer was oxidized to form a gate insulating film 13 of about 500 nm made of silicon oxide. Subsequently, gold was vacuum-deposited with a thickness of about 10 nm on the gate insulating film 13 and patterned by lithography and etching to form the source electrode 14 and the drain electrode 15. The distance between the source electrode 14 and the drain electrode 15 is about 5 μm, for example.

As shown in FIG. 5B, a modification film 16 made of a silane compound was formed on the gate insulating film 13. By forming the modification film 16, the threshold voltage (V _th ) of the organic thin film transistor can be controlled to a desired value. CF ₃ (CF ₂ ) ₇ (CH ₂ ) ₂ Si (OC ₂ H ₅ ) ₃ was used as the silane compound. As a method for forming the modification film 16, a spin coating method is used, but another liquid phase method such as a dipping method or a vapor phase method such as a CVD method may be used.

  As shown in FIG. 5C, the organic thin film transistor 10 is manufactured by bonding the organic semiconductor thin film 17 made of the single crystal obtained in the process shown in FIG. 4 on the modification film 16 by natural electrostatic attraction. Is done. According to this method, a transistor having no crystal grain boundary and a flat contact surface with the gate insulating film 13 on a molecular scale is formed.

<Experimental result>
Next, transfer characteristics of the organic field effect transistor 1 according to the present embodiment were measured. FIG. 6 is a diagram showing the transfer characteristic (change in conductivity σ with respect to the gate voltage V _G ) of the organic field effect transistor 1 when V _D (drain voltage) = − 50 (V) is fixed.

From the results shown in FIG. 6, anti-type bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin is p-type with a negative threshold voltage. It can be seen that the semiconductor characteristics are as follows. When calculated from the graph shown in FIG. 6, the mobility μ of this device was 3.0 × 10 ⁻³ cm ² / Vs, and the threshold voltage Vth was about −20V.

  In the second embodiment, the example in which the organic semiconductor single crystal is first prepared and attached to the substrate has been described. However, the same manufacturing method as in the first embodiment may be employed. In addition, the organic semiconductor material of Example 1 may be manufactured in the same manner as in Example 2.

  Below, the synthesis method of various compounds is demonstrated. In the following, bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin is the target compound 1 and bis (benzo [4,5] thieno. ) [2,3-b: 2′3′-e] [1,4] dithiin is referred to as the target compound 5. Non-patent literature 1 discloses a conventional example of a method for synthesizing these target compounds.

<Outline of Synthesis Method of Target Compound 1>
As shown below, bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin (target compound 1) is benzo [b] thiophene (compound It is synthesized from 2) through 3-bromobenzo [b] thiophene (compound 3) and 3,3′-bis (benzo [b] thienyl) sulfide (compound 4).

In the above synthesis method, the target compound 1 was synthesized in 29% yield using the compound 4 as a raw material. In the above synthesis method, the target compound 1 was synthesized by dilithiating the compound 4 using tBuLi and TMEDA and then adding sulfur dichloride. However, this method is considered to have a low yield due to a problem in the step of generating a dianion in the molecule by deprotonation with an organic base. This is presumed to originate from a change in the acidity of protons in the process of conversion from neutral molecules to monoanions and then to dianions. The synthesis method of the target compound 1 by the improved method is shown below. The improved method was able to increase the yield to 44%.

  In the improved method, a dibromo form was formed using 2 equivalents of bromine for compound 4, then converted to a dianion form using tBuLi without purification, and then sulfur dichloride was added to lead to target compound 1. In this method, since the dianion body can be generated by a metal-halogen exchange reaction without directly deprotonating the compound 4, it is considered that the reaction progressed without depending on the change in acidity. This improved method is a very useful method in which the yield is increased from 29% of the general method to 44%.

The synthesis method of target compound 1 by the general method (step A) and the synthesis method of target compound 1 by the improved method (step B) are described in detail below.
<Process A>
Compound 4 (298 mg: 1.0 mmol) and a stirring bar were placed in a 100 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. Et ₂ O (50 ml) and TMEDA (0.30 ml: 2.0 mmol) were added and the reaction vessel was cooled to −30 ° C., and then a 1.43 M ^t BuLi pentane solution (1.40 ml: 2.0 mmol) was added. In addition, the mixture was stirred at −30 ° C. for 1 hour. Next, sulfur dichloride (0.063 ml: 1.0 mmol) diluted with Et ₂ O (30 ml) was slowly added dropwise. After completion of the addition, the mixture was stirred at room temperature for 18 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. After extraction with methylene chloride, the organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed with a rotary evaporator. The target compound 1 (95 mg: 0.289 mmol: 29%) was separated and purified by silica gel column chromatography using hexane as a developing solvent. The obtained target compound 1 was colorless crystals and had a melting point of 195.0-196.0 ° C. The structural data of the compound was as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 7.34 (t, 2H, J = 7.8 Hz, ArH), 7.41 (t, 2H, J = 7.8 Hz, ArH), 7.71 (d, 2H, J = 7.8 Hz, ArH), 7.76 (d, 2H, J = 7.8 Hz, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 120.9, 122.5, 125.0, 125.1, 126.4, 129.9, 136.5, 141.0; IR (KBr) ν1433, 1314, 1250, 744, 720 cm ⁻¹ ; MS (70 eV) m / z 328 (M ⁺ ); Anal. Calcdfor C ₁₆ H ₈ S ₄ : C, 58.50; H, 2.45%. Found: C, 58.18; H, 2.78%.

<Process B>
Compound 4 (3.219 g: 10.786 mmol) and a stirring bar were placed in a 200 ml three-necked flask, dissolved in 100 ml of CH ₂ Cl ₂ , and then the reactor was cooled to 0 ° C. Bromine (1.13 ml: 22.0 mmol) diluted with 20 ml of CH ₂ Cl ₂ was slowly added dropwise thereto over 80 minutes, and after completion of the addition, the reactor was stirred at room temperature for 14 hours. An aqueous sodium hydrogen sulfite solution was poured into the reaction vessel, and the organic phase was washed. The reaction solution was separated with a separatory funnel, and the organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed with a rotary evaporator. A pale yellow solid (4.025 g: 8.822 mmol: 82%) that appears to be 2,2′-dibromo-3,3′-bis (benzo [b] thienyl) sulfide by silica gel column chromatography using hexane as a developing solvent. Was separated and purified. This pale yellow solid (456 mg: 1.0 mmol) and a stirring bar were placed in a 200 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. Dehydrated Et ₂ O (80 ml) was added, the reaction vessel was cooled to −30 ° C., 1.60 M ^t BuLi pentane solution (1.25 ml: 2.0 mmol) was added, and the mixture was stirred at −30 ° C. for 40 minutes. . Next, sulfur dichloride (0.063 ml: 1.0 mmol) was slowly added dropwise, and after completion of the addition, the mixture was stirred at room temperature for 11 hours. The solvent was removed by a rotary evaporator, water was poured into the resulting reaction mixture, and hydrochloric acid was added to adjust to pH = 1. Extraction was performed with chloroform, and the organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed with a rotary evaporator. The target compound 1 (145 mg: 0.441 mmol: 44%) was separated and purified as a pale yellow solid by silica gel column chromatography using hexane as a developing solvent. The structural data of the compound was as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 7.26-7.33 (m, 4H, ArH), 7.66-7.70 (m, 2H, ArH), 7.76-7.80 (m, 2H, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 121.4, 121.9, 122.8, 124.6, 125.2, 125.3, 138.9, 139.1.

<Outline of Synthesis Method of Target Compound 5>
As shown below, bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin (target compound 5) is benzo [b] thiophene (compound It is synthesized from 2) through 2-mercaptobenzo [b] thiophene (compound 6) and 2,3′-bis (benzo [b] thienyl) sulfide (compound 7).

  In the conventional method, the target compound 5 was synthesized in 13% yield via the above compounds 6 and 7. In the conventional method, the synthesis yield from compound 2 to compound 6 as the initial raw material was 55%, and the subsequent synthesis yield from compound 6 to compound 7 was 84%, and the total yield up to compound 7 was 46%. It was. This is presumably because Compound 6 is unstable to air, and there was a problem during the purification operation of Compound 6 and the pre-reaction stage of Compound 7, resulting in a moderate yield. In the improved method, the yield of compound 7 was improved by changing the intermediate compound, and a mass synthesis method for target compound 5 was established.

<Improvement of Synthesis of Compound 7>
As shown below, in the improved method, compound 7 is synthesized from compound 2 via 2-acetylthiobenzo [b] thiophene (compound 8).

  In the improved method, Compound 8 in which the thiol group that is the center of instability of Compound 6 was replaced with a relatively stable acetylthio group was used as a synthetic equivalent of Compound 6. After lithiation of benzo [b] thiophene with BuLi, elemental sulfur is added, followed by protonation, hydride reduction with an inorganic reducing agent, and acetylation with acetic anhydride to stabilize compound 8 in a stable, colorless yield of 77%. Isolated as crystals. Next, compound 7 was synthesized in a yield of 95% by reacting compound 8 with 3-bromobenzo [b] thiophene (compound 3), copper iodide, and potassium hydroxide. This improved method is extremely useful in that the total yield up to compound 7 is improved from 46% to 73% of the conventional method by not passing through unstable compound 6 but via compound 8 which is a stable synthetic equivalent. Is the method. Further, Compound 6 is a compound that generates an unpleasant odor, while Compound 8 is odorless, so that the method via Compound 8 is very effective not only for yield but also for handling.

<Improvement of synthesis of target compound 5>
In the conventional method, the synthesis yield of compound 7 from raw material 7 is as low as 13%, and the reagent for the sulfurization cyclization reaction at that time is expensive bis (phenylsulfonyl) sulfide. In this reaction system, reagents for the sulfurization cyclization reaction are expensive, and 90% by weight of them is discarded, so it is considered not suitable for mass synthesis. An improved method for the synthesis of target compound 5 is shown below.

In the improved method, a reaction capable of mass synthesis was designed in consideration of the following two points. The first improvement is that the compound 7 is brominated and then the metal-halogen exchange is performed to increase the production rate of the dianion.
This enables dilithiation without going through deprotonation due to the difference in acidity of protons at different positions. The second improvement is the use of inexpensive sulfur dichloride as a reagent. The experimental procedure is as follows. Compound 7 was synthesized in a yield of 8% by adding 2 equivalents of bromine to compound 7 to obtain a dibromo compound, followed by dilithiation with tBuLi and a sulfurization cyclization reaction using sulfur dichloride. Although this improved method is inferior in yield compared to the conventional method, it is an extremely useful method capable of large-scale synthesis because an inexpensive reagent is used.

  Below, the detail of each process CH by the conventional method and improvement method until synthesize | combining the target compound 5 is demonstrated.

<Step C: Synthesis of Compound 6>
Compound 2 (13.420 g: 100.0 mmol) and a stirrer were placed in a 300 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. Dehydrated Et ₂ O (200 ml) was added, the reaction vessel was cooled to −15 ° C., 2.44 M ⁿ BuLi in hexane (40.98 ml: 110.0 mmol) was added, and the mixture was stirred at −15 ° C. for 30 minutes. . Next, elemental sulfur (7.697 g: 240.0 mmol) was slowly added and stirred at room temperature for 11 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. Extraction was performed with CH ₂ Cl ₂ , and the organic layer was dried over anhydrous sodium sulfate and filtered, and then the solvent was removed with a rotary evaporator. The resulting reaction mixture was dissolved in THF (100 ml), sodium borohydride (3.782 g: 100.0 mmol) was slowly added at room temperature, and the mixture was stirred as it was for 1 hour. Water is poured into the reaction solution, and hydrochloric acid is added to adjust to pH = 1. After extraction with Et ₂ O, the organic phase is made basic by adding 5M aqueous sodium hydroxide solution, the aqueous phase is separated, and hydrochloric acid is added to the aqueous phase. PH = 1. Extraction was performed with CH ₂ Cl ₂ , and the organic layer was dried over anhydrous sodium sulfate and filtered, and then the solvent was removed with a rotary evaporator. Compound 6 (9.156 g: 55.07 mmol: 55%) was separated and purified as a white solid by silica gel column chromatography using hexane as a developing solvent. The structural data of the compound was as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 3.67 (d, 1H, J = 1.0 Hz, SH), 7.26 (brs, 1H, ArH) 7.29 (dd, 1H, J = 7.5, 1 .7 Hz, ArH), 7.30 (dd, 1H, J = 7.2, 1.4 Hz, ArH), 7.65 (dd, 1H, J = 6.9, 2.0 Hz, ArH), 7. 70 (dd, 1H, J = 7.0, 1.8 Hz, ArH).

<Step D: Synthesis of Compound 7>
In a 100 ml three-necked flask, compound 6 (6.291 g: 37.84 mmol), compound 3 (8.064 g: 37.84 mmol), copper iodide (7.207 g: 37.84 mmol), potassium hydroxide (2. 123 g: 37.84 mmol) and a stirring bar were added, and the inside of the reaction vessel was purged with nitrogen. Dehydrated DMF (37.84 ml) was added and stirred at 130-140 ° C. for 30 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. The insoluble material was filtered off with suction, and the reaction solution was extracted with CH ₂ Cl _{2. The} organic layer was dried over anhydrous sodium sulfate and filtered, and then the solvent was completely removed with a rotary evaporator and a suction pump. Compound 7 (9.507 g: 31.85 mmol: 84%) was separated and purified as colorless flake crystals by silica gel column chromatography using hexane as a developing solvent from the resulting reaction mixture. The melting point of the obtained compound 7 was 83.0-84.0 ° C., and the structural data were as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 7.23 (td, 1H, J = 7.5, 1.4 Hz, ArH), 7.28 (td, 1H, J = 7.5, 1.4 Hz, ArH), 7.31 (s, 1H, ArH), 7.37 (td, 1H, J = 6.2, 1.9 Hz, ArH), 7.40 (td, 1H, J = 6.2, 1.8 Hz, ArH), 7.62 (td, 2H, J = 7.5, 1.4 Hz, ArH), 7.69 (s, 1H, ArH), 7.85 (dd, 1H, J = 6.2, 1 .9 Hz, ArH), 7.97 (dd, 1H, J = 6.2, 1.8 Hz, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 121.8, 122.7, 122.9, 123. 0,124.3,124.4,124.8,124.95,125.02,126.6,130.8 ^{136.6,138.4,139.7,139.8,141.3; IR (KBr) ν1422,833,760,751,733cm -1} ; MS (70eV) m / z298 (M +); Anal. Calcdfor C ₁₆ H ₁₀ S ₃ : C, 64.39; H, 3.38%. Found: C, 64.54; H, 3.44%.

<Step E: Synthesis of target compound 5>
Compound 7 (298 mg: 1.0 mmol) and a stirring bar were placed in a 100 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. Et ₂ O (30 ml) and TMEDA (0.30 ml: 2.0 mmol) were added, the reaction vessel was cooled to −30 ° C., and then a 1.43 M ^t BuLi pentane solution (1.40 ml: 2.0 mmol) was added. In addition, the mixture was stirred at −30 ° C. for 1 hour. Next, bis (phenylsulfonyl) sulfide dissolved in Et ₂ O (30 ml) and THF (15 ml) was slowly added dropwise. After completion of the addition, the mixture was stirred at room temperature for 18 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. Extraction was performed with methylene chloride and chloroform, and the organic layer was dried over anhydrous magnesium sulfate, filtered, and then the solvent was removed with a rotary evaporator. The target compound 5 (43 mg: 0.131 mmol: 13%) as colorless crystals was separated and purified by silica gel column chromatography using hexane as a developing solvent. The melting point of the obtained compound 5 was 207.0-208.3 ° C., and the structure data was as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 7.34 (t, 2H, J = 7.4 Hz, ArH), 7.41 (t, 2H, J = 7.4 Hz, ArH), 7.69 (d, 2H, J = 7.9 Hz, ArH), 7.73 (d, 2H, J = 8.0 Hz, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 120.6, 122.5, 124.9, 125.0 , 125.7, 131.3, 136.3, 140.9; IR (KBr) ν 1478, 1454, 1419, 1251, 1018, 910, 741, 718 cm ⁻¹ ; MS (70 eV) m / z 328 (M +); Anal. _{Calcd for C 16 H 8 S 4} : C, 58.50; H, 2.45%. Found: C, 58.48; H, 2.57%.

<Step F: Synthesis of Compound 8>
Compound 2 (13.420 g: 100.0 mmol) and a stirrer were placed in a 300 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. Dehydrated Et ₂ O (200 ml) was added, the reaction vessel was cooled to −15 ° C., 2.55 M ⁿ BuLi in hexane (43.14 ml: 110.0 mmol) was added, and the mixture was stirred at −15 ° C. for 1 hour. . Next, elemental sulfur (3.848 g: 1/8 S ₈ 110.0 mmol) was slowly added and stirred at room temperature for 4 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. Extraction was performed with CH ₂ Cl ₂ , and the organic layer was dried over anhydrous sodium sulfate and filtered, and then the solvent was removed with a rotary evaporator. The obtained reaction mixture was dissolved in THF (100 ml), sodium borohydride (1.891 g: 50.0 mmol) was slowly added at room temperature, and the mixture was stirred as it was for 30 minutes. Acetic anhydride (18.8 ml: 200 mmol) was slowly added thereto and stirred at room temperature for 30 minutes. Water was poured into the reaction solution, and the mixture was extracted with methylene chloride. The organic layer was dried over anhydrous magnesium sulfate, filtered, and the solvent was removed with a rotary evaporator. Methylene chloride was added to the resulting reaction mixture, and an insoluble solid was filtered off. Then, recrystallization was repeated twice with methylene chloride, whereby colorless crystals of compound 8 (11.85 g + 4.157 g: 77.014 mmol: 77% ) Was separated and purified. The melting point of Compound 8 obtained was 91.5-92.0 ° C., and the structural data were as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 2.45 (s, 3H, Acetyl), 7.357 (t, 1H, J = 6.6 Hz, ArH), 7.365 (t, 1H, J = 6.5 Hz, ArH), 7.43 (s, 1H, thiophene-H), 7.78 (dd, 1H, J = 6.4, 3.1 Hz, ArH), 7.81 (dd, 1H, J = 6.8) , 3.6 Hz, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 29.8, 122.1, 124.0, 124.5, 125.3, 127.1, 132.4, 139.3, 143 , 2, 193.2; IR (KBr) ν 1703, 1107, 955, 750, 612 cm ⁻¹ ; MS (70 eV) m / z 208 (M ⁺ ); Anal. _{Calcd for C 10 H 8 OS 2} : C, 57.66; H, 3.87%. Found: C, 57.85; H, 3.83%.

<Step G: Synthesis of Compound 7>
In a 300 ml two-necked flask, compound 8 (10.415 g: 50.00 mmol), compound 3 (10.655 g: 50.00 mmol), copper iodide (9.525 g: 50.00 mmol), potassium hydroxide (5. 611 g: 100.00 mmol) and a stir bar, and the inside of the reaction vessel was purged with nitrogen. Dehydrated DMF (50.00 ml) was added and stirred at 130-140 ° C. for 34 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. The insoluble material was filtered off with suction, and the reaction solution was extracted with CH ₂ Cl _{2. The} organic layer was dried over anhydrous sodium sulfate and filtered, and then the solvent was removed with a rotary evaporator. The obtained reaction mixture was adsorbed onto silica gel using CH ₂ Cl ₂ , dried and then eluted with hexane to obtain a white solid. The white solid was recrystallized from hexane, and the compound 7 (8.582 g + 5.521 g: 47.25 mmol: 95%) was separated and purified as colorless flake crystals by silica gel column chromatography using hexane as a developing solvent in the filtrate. did.

<Step H: Synthesis of target compound 5>
Compound 7 (5.969 g: 20.0 mmol) and a stir bar were placed in a 300 ml three-necked flask and dissolved in 100 ml of CH ₂ Cl ₂ . Bromine (2.06 ml: 40.0 mmol) diluted with 50 ml of CH ₂ Cl ₂ was slowly added dropwise thereto, and the reactor was stirred at room temperature for 30 hours after completion of the addition. An aqueous sodium hydrogen sulfite solution was poured into the reaction vessel, and the organic phase was washed. The reaction solution was separated with a separatory funnel, and the organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed with a rotary evaporator. Of 5.926 g of the obtained solid, 5.750 g and a stirring bar were placed in a 300 ml three-necked flask, and the inside of the reaction vessel was purged with nitrogen. After adding dehydrated THF (100 ml) and cooling the reaction vessel to −78 ° C., a 1.59 M ^t BuLi pentane solution (31.706 ml: 50.512 mmol) was added and stirred at −78 ° C. for 10 minutes. Next, sulfur dichloride (0.791 ml: 12.603 mmol) diluted with dry THF (50 ml) was slowly added dropwise. After completion of the addition, the mixture was stirred at room temperature for 18.5 hours. Water was poured into the reaction solution, and hydrochloric acid was added to adjust to pH = 1. Extraction was performed with CH ₂ Cl ₂ , and the organic layer was dried over anhydrous magnesium sulfate and filtered, and then the solvent was removed with a rotary evaporator. Next, recrystallization using CH ₂ Cl ₂ was performed twice to obtain pale yellow crystals (38 mg + 464 mg: 8%) of the target compound 5. The melting point of the target compound 5 was 207.0-208.3 ° C., and the structural data were as follows.
¹ HNMR (400 MHz, CDCl ₃ ) δ 7.34 (t, 2H, J = 7.4 Hz, ArH), 7.41 (t, 2H, J = 7.4 Hz, ArH), 7.69 (d, 2H, J = 7.9 Hz, ArH), 7.73 (d, 2H, J = 8.0 Hz, ArH); ¹³ C NMR (101 MHz, CDCl ₃ ) δ 120.6, 122.5, 124.9, 125.0 , 125.7, 131.3, 136.3, 140.9; IR (KBr) ν 1478, 1454, 1419, 1251, 1018, 910, 741, 718 cm ⁻¹ ; MS (70 eV) m / z 328 (M ⁺ ) Anal. _{Calcd for C 16 H 8 S 4} : C, 58.50; H, 2.45%. Found: C, 58.48; H, 2.57%.

It is sectional drawing of the organic thin-film transistor which concerns on this embodiment. It is process sectional drawing which shows manufacture of the organic thin-film transistor which concerns on this embodiment. Is a diagram showing the I _D -V _G characteristics of the organic thin film transistor of the embodiment. FIG. 6 is a process diagram illustrating the production of the organic thin film transistor of Example 2. FIG. 6 is a process diagram illustrating the production of the organic thin film transistor of Example 2. He is a diagram showing a sigma-V _G characteristics of the organic thin film transistor of Example 2.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Organic thin-film transistor, 11 ... Substrate, 12 ... Gate electrode, 13 ... Gate insulating film, 14 ... Source electrode, 15 ... Drain electrode, 16 ... Modification film, 17 ... Organic-semiconductor thin film

Claims (10)

General formula

An organic semiconductor compound represented by:
(In the formula, A and B are electron conjugated aromatic rings, X and Y are DR ₂ , ER and G, respectively. D is any one of C, Si, Ge and Sn, and E is N, (It is any one of P, As, and Bi, G is any one of O, S, Se, and Te. R is any one of H, an alkyl group, and an aryl group.) Structural formula

Bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin represented by:
The organic semiconductor compound according to claim 1. Structural formula

Bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by:
The organic semiconductor compound according to claim 1.   The organic-semiconductor thin film containing the organic-semiconductor compound in any one of Claims 1-3.   The organic-semiconductor coating liquid containing the organic-semiconductor compound in any one of Claims 1-3, and the solvent which can melt | dissolve the said organic-semiconductor compound. The solvent includes at least one of hydrocarbon, alcohol, ether, ester, halogen, ketone, nitrile, BTX, aprotic polar solvent,
The organic-semiconductor coating liquid of Claim 5. An organic thin film transistor comprising an organic semiconductor thin film as an active layer, wherein the organic semiconductor thin film contains the organic semiconductor compound according to any one of claims 1 to 3.
Organic thin film transistor. Structural formula

A dibromo form of 3,3′-bis (benzo [b] thienyl) sulfide represented by the formula: wherein the dibromo form is converted into a dianion form, and sulfur dichloride is added.

A bis (benzo [4,5] thieno) [2,3-b: 3′2′-e] [1,4] dithiin represented by the formula: Structural formula

From the benzo [b] thiophene represented by the structural formula

And 2,3′-bis (benzo [b] thienyl) sulfide represented by the structural formula

A bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by the formula:
From benzo [b] thiophene, the structural formula

Bis (benzo [4,5] thieno) [2], characterized in that 2,3′-bis (benzo [b] thienyl) sulfide is produced via 2-acetylthiobenzo [b] thiophene represented by , 3-b: 2′3′-e] [1,4] dithiin production method. Structural formula

The structure represented by the structural formula is characterized in that the 2,3′-bis (benzo [b] thienyl) sulfide represented by the following formula is converted into a dibromo form, and then the dibromo form is dilithiated and subjected to a sulfurization cyclization reaction.

A bis (benzo [4,5] thieno) [2,3-b: 2′3′-e] [1,4] dithiin represented by the formula:

Images